1. Field of the Invention
The present invention relates to a caster device, and more specifically, to a caster device with a directional mechanism.
2. Description of the Prior Art
In modern life, a hand propelled vehicle with a wheel device, such as a stroller, a supermarket cart, a luggage case or an ambulance bed, is widely utilized. The wheel devices for the hand propelled vehicle are generally divided into a directional wheel device and a universal wheel device, based on purposes and requirements of the vehicles. In general, the hand propelled vehicle with the directional wheel device only can be moved in a straight line, so as to ensure stability and directionality of the hand propelled vehicle. However, it is difficult to turn the hand propelled vehicle due to the fixed moving direction of the directional wheel device. As for the hand propelled vehicle with the universal wheel device, since the wheel may rotate in 360 degrees rotation, it may facilitate a user to turn the hand propelled vehicle. However, flexibility of the hand propelled vehicle with the universal wheel device sacrifices stability and directionality. Therefore, it is better to combine advantages and characteristics of the directional wheel device and the universal wheel device for designing a vehicle product, so that the vehicle product can have advantages of the directional wheel device and the universal wheel device at the same time.
Therefore, some manufacturers dispose a directional mechanism on the universal wheel device, so that the universal wheel device can act as the directional wheel device. For example, China application NO. ZL97201025.4 filed in 1998 Nov. 18 discloses an automatic directional movable castor, and a directional mechanism of the caster includes a directional pin, a directional group, a spring and a plurality of directional hole pits. The spring covers the directional pin and is elastically disposed on the directional group. The circumference of a protecting cover of the caster is provided with the plurality of hole pits for the directional pin. The directional group is disposed near the protecting cover of the caster. A principle of orientation is that the pin is pushed by the spring, so that an inserting part of the directional pin protrudes from the directional group to insert into and to contact with the corresponding hole pit. Therefore, a movable caster bracket capable of pivoting is fixed in a directional state and cannot be turned. However, because the directional pin is disposed on the directional mechanism, and the directional mechanism is near the protecting cover of the caster, the directional pin cannot be inserted into the corresponding hole pit rapidly for locking the caster bracket to ensure the directional function. Moreover, a directional effect of this directional mechanism is poor, so that the castor is easily turned from the directional state to a universal state as the castor is turned. Therefore, it is necessary to provide a mechanical design to solve above problems.